CN207586405U - A kind of DC power supply monitoring system based on usb data capture card - Google Patents

Abstract

The utility model discloses a DC power supply monitoring system based on a USB data acquisition card, which comprises a power supply unit, a DC voltage sensor, a DC current sensor, a signal conditioning circuit, a high-speed USB data acquisition card and an upper computer. The current and voltage sensor module collects the DC power supply voltage and current parameters, and converts them into data acquisition cards that can receive signals through the signal conditioning circuit. The data acquisition card performs AD conversion on the collected current and voltage signals at the same time, and the converted data is transmitted to the The upper computer, the upper computer LabVIEW software performs data analysis on the results, and the analysis results are displayed and saved in real time. The USB data acquisition card mentioned above provides a high data sampling rate and transmission rate under the condition of ensuring low cost. The high-performance host computer can quickly analyze a large amount of data, display and store the data and its analysis results in real time, and reduce the system cost. The development cost is reduced, and the accuracy and real-time performance of the monitoring system are improved.

Description

A DC Power Monitoring System Based on USB Data Acquisition Card

technical field

The utility model relates to the field of DC power supply monitoring and protection, in particular to a monitoring system which collects current and voltage data and transmits them to a host computer at high speed, and the host computer analyzes power quality and circuit faults in real time.

Background technique

DC power supply is widely used in various occasions such as consumer electronics, automatic control, relay protection, audio lighting, electronic equipment, and electric transportation. The instability of current and voltage and electrical failure under DC power supply will cause unstable operation of equipment and even accidents. . When the power quality of the low-voltage DC system deteriorates and various DC faults occur, due to the characteristics of DC power, it is often necessary to analyze the high-frequency dynamic characteristics of DC voltage and current, and the amount of data to be analyzed is relatively large. The data acquisition module and data transmission module are required to have Higher data acquisition rate and transmission rate, meanwhile, the host computer must have a faster data processing speed to complete high-speed dynamic data analysis and display the final processing results.

The existing DC monitoring system basically uses the RS serial interface to transmit data, and the data transmission rate is relatively slow. When the speed of the signal acquisition module is fast, the data transmission module cannot transmit data to the host computer in time, and the display of the host computer will be delayed; on the other hand, the lower transmission rate affects the data analysis of the host computer, and even cannot obtain useful information As a result, the effectiveness of monitoring and the functionality of the system are reduced.

Utility model content

In view of the above situation, the utility model provides a low-voltage DC monitoring system based on LabVIEW and high-speed USB acquisition card, the purpose is to accurately analyze the parameters of the DC low-voltage circuit, display its status in real time, and issue a fault alarm when encountering a fault.

In order to achieve the above object, the utility model adopts the following technical scheme: a DC power monitoring system based on a USB data acquisition card, consisting of a power supply unit, a DC voltage sensor, a DC current sensor, a signal conditioning circuit, a high-speed USB data acquisition card and a host computer : The power supply unit converts 220V AC to 3.3V or 5V to provide power to the voltage and current sensor, signal conditioning circuit and data acquisition card. The coil of the current sensor is passed through the positive wire of the DC power system, and the input terminals of the voltage sensor are respectively connected to the positive and negative On the wire, the output ends of the current and voltage sensors are respectively connected to the input ends of the signal conditioning circuit to filter and amplify the signal, the output ends of the current and voltage signal conditioning circuit are respectively connected to the AD port of the data acquisition card, and the output end of the data acquisition card is connected to the host computer through the USB interface. The upper computer is equipped with LabVIEW software to receive data and perform real-time data processing and analysis, display and store the analysis results.

The power supply unit is used to provide power to the signal conditioning circuit and the data acquisition card.

The sensor unit is composed of a DC current transformer and a Hall voltage sensor. The current transformer can collect 0-10A DC current, and the voltage dividing resistor can collect 0-400V DC voltage, which is used to collect the current and voltage in the low-voltage DC line. parameter.

The signal conditioning circuit is composed of a differential input circuit, a high-low pass filter, and a signal conversion circuit, and is mainly used for signal amplitude conversion to meet the input requirements of the signal acquisition card.

The high-speed USB data acquisition card contains multiple AD ports, which can complete AD conversion in parallel, and transmit it to the host computer through the USB 2.0 high-speed interface.

The upper computer is equipped with LabVIEW software, which displays and saves power quality parameters in real time, and judges whether there is an electrical fault and whether an alarm is given.

The beneficial effect of the utility model is that: adopting the USB data acquisition card provides a higher data sampling rate and transmission rate under the condition of ensuring low cost, so that the analyzable frequency domain characteristics of the data are wider, providing further information on the power state and Fault analysis provides a data basis; the upper computer uses a high-performance PC and LabVIEW software using a graphical programming language, which can quickly analyze a large amount of data, display and store data and analysis results in real time, reducing system development costs and improving monitoring. The accuracy and real-time performance of the system.

Description of drawings

Fig. 1 is a schematic structural diagram of a DC power monitoring system based on a USB data acquisition card of the present invention.

Fig. 2 is a flow chart of data processing of a DC power monitoring system based on a USB data acquisition card of the present invention.

Reference signs: (1) power supply unit; (2.1) current sensor; (2.2) voltage sensor; (3.1) current signal conditioning circuit; (3.2) voltage signal conditioning circuit; (4) data acquisition card; (5) host computer .

Detailed ways

Further description will be made below in conjunction with the accompanying drawings.

As shown in Figure 1, a DC power monitoring system based on a USB data acquisition card includes a power supply unit (1), a DC voltage sensor (2.1), a DC current sensor (2.2), a current signal conditioning circuit (3.1), and a voltage signal conditioning circuit (3.2), high-speed USB data acquisition card (4) and host computer (5): the power supply unit (1) converts the power grid 220V to 3.3V or 5V voltage, and supplies the signal conditioning circuit (3) and data acquisition card (4) Provide power supply, the sensor unit (2) collects the current and voltage parameters of the power supply DC line, the sensor output terminal is connected to the input terminal of the signal conditioning circuit (4) to filter and amplify the signal, and then output the signal to the AD port of the data acquisition card (4) , the data acquisition card (4) transmits the data after AD conversion to the upper computer (5) through the USB interface, and the upper computer (5) is equipped with LabVIEW software to receive the data and perform real-time data processing and analysis, and display and store the analysis results.

The power supply unit (1) is used to provide power to the signal conditioning circuit (3) and the data acquisition card (4).

The DC current sensor (2.1) is composed of a DC current transformer. The current transformer can collect 0-10A DC current and output a voltage signal of 0-5V for collecting current parameters in low-voltage DC lines.

The DC voltage sensor (2.2) is composed of a Hall voltage sensor module, the current transformer can collect 0-400V DC voltage, and the output is 0-5V voltage, which is used to collect voltage parameters in low-voltage DC lines.

The current signal conditioning circuit (3.1) is composed of a differential input circuit, a high-low pass filter, and a signal conversion circuit, and is mainly used for amplitude conversion and filtering of the DC current signal, so as to meet the requirements of the AD port of the signal acquisition card for the input signal .

The voltage signal conditioning circuit (3.2) is composed of a differential input circuit, a high-low pass filter, and a signal conversion circuit, and is mainly used for performing amplitude conversion and filtering on the DC voltage signal to meet the requirements of the AD port of the signal acquisition card for the input signal .

The high-speed USB data acquisition card (4) has 24 differential input analog signal-digital signal (AD) conversion channels, the highest sampling rate is 50kHz, and has a USB 2.0 high-speed interface to connect with the host computer (5).

The upper computer (5) is equipped with LabVIEW software for real-time display of power state parameters such as DC current voltage deviation, fluctuations, harmonics, transient overcurrent voltage, and the analysis results and the upper limit value of the normal working power index Compare and judge whether the line is safe and reliable and give sound and light alarm.

As shown in Figure 2, the sensor module collects the DC power supply voltage and current parameters, and the signal conditioning circuit converts the data acquisition card to receive the signal. The data acquisition card performs AD conversion on the collected current and voltage signals at the same time, and the converted data passes through The USB interface is transmitted to the host computer, and the LabVIEW software of the host computer performs data analysis on the results, and the analysis results are displayed and saved in real time.

Here, some features and a method of implementation of the utility model are described, but other structural changes, substitutions and modifications based on the technical solution of the utility model should also be included in the protection scope of the utility model claims, and the specific protection scope The scope of the appended claims shall prevail.

Claims (4)

1. A DC power monitoring system based on a USB data acquisition card is composed of a power supply unit, a DC voltage sensor, a DC current sensor, a signal conditioning circuit, a high-speed USB data acquisition card and an upper computer, and is characterized in that: the output terminal of the power supply unit is connected The voltage and current sensor, signal conditioning circuit and data acquisition card provide power supply. The coil of the current sensor is passed through the positive wire of the DC power supply system. The input terminals of the voltage sensor are respectively connected to the positive and negative wires of the DC power supply. The input terminal of the conditioning circuit and the output terminal of the current and voltage signal conditioning circuit are respectively connected to the AD port of the data acquisition card, and the output terminal of the data acquisition card is connected to the host computer through the USB interface. 2. A kind of DC power monitoring system based on USB data acquisition card according to claim 1, is characterized in that, described USB data acquisition card sampling rate is 50kHz, has 24 road AD channels. 3. A kind of DC power monitoring system based on USB data acquisition card according to claim 1, is characterized in that, current sensor adopts DC current transformer. 4. The DC power monitoring system based on a USB data acquisition card according to claim 1, wherein the voltage sensor adopts a Hall voltage sensor module.